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● Custom object ● Note: An object name starting with "my" indicates an instance of the custom object.If the = sign is added before the function name, the function returns a value. 1. Basic Object ):New object ([expression])Object (expression)Defines

For two relations a and B, the Union keyword Concatenates the two into a single relationship that only contains non-duplicate fields A and B. In SQL, Union joins two select results, and deduplication is eliminated by default (all data is retained

  Common SQL date format conversion methods Posted by Ouyang Zhenhua on 8:46:20 Select CONVERT (varchar (12), getdate (), 101) 09/12/2004   Select CONVERT (varchar (12), getdate (), 103) 12/09/2004   Select CONVERT (varchar (12), getdate ()

Coalesce Returns the first non-empty expression in the parameter. Syntax Coalesce (expression [,... n]) parameter Expression any type of expression. N indicates that placeholders of multiple expressions can be specified. All expressions must be of

Coalesce usage: Returns the first non-empty expression in its argument. Transact-SQL Syntax conventions Grammar COALESCE (expression [,... n]) Parameters Expression An expression of any type. return type Returns the data type of the expression

COALESCE (expression_1, expression_2, ..., expression_n) refer to each parameter expression in turn, and then stop and return the value if it encounters a non-null value. If all of the expressions are NULL, a null value will eventually be returned.

We all know the usage of Casewhen. Once a certain WHEN is satisfied, the data will exit the CASEWHEN instead of considering other cases, this article introduces the usage of casewhen in detail and gives an example. We all know the usage of Case when.

Case when usage, simple Case FunctionUse a simple CASE expression to determine the return value. Syntax: CASE search_expression WHEN expression1 THEN result1 WHEN expression2 THEN result2 ... WHEN expressionN THEN resultN ELSE default_result Search

1. coalesce () function --- Introduction ---The coalesce () function of the T-SQL allows you to specify multiple expressions, and coalesce () returns the first non-null value in the group. Use the following format, where expression can be any data

EXCEPT/INTERSECT, CASE/ISNULL/COALESCE in SQL SERVEREXCEPT and INTERSECT General explanation: Compare the results of two queries and return non-repeated values. EXCEPTFrom the left query, all non-repeated values not found in the right query are